Turn control apparatuses for a vehicle have been disclosed, it, for example, in Unexamined Japanese Patent Publication No. 1-237252 and Unexamined Japanese Patent Publication No. 3-143757. In the control apparatus disclosed in the former Publication, when a vehicle turns while being braked, the braking force on the right and left rear wheels is increased or decreased according to the yaw angular velocity of the vehicle. Thereby, a yaw moment can be produced on the vehicle to prevent a spin thereof. In the control apparatus in the latter Publication, the braking force on the front and rear wheels is controlled according to the turning condition of the vehicle when the vehicle turns while being braked. Thereby, a yaw moment can be produced on the vehicle to assist a turning thereof.
For the control apparatus in the former Publication, the braking force on only the right and left rear wheels of the vehicle is controlled, so that the yaw moment generated on the vehicle by this control is relatively small. Therefore, there is a possibility that a spin of the vehicle cannot be prevented effectively depending on the turning condition of the vehicle.
For the control apparatus in the latter Publication, the braking force on all of four wheels of the vehicle are controlled. Therefore, even if the driver attempts to apply a stronger braking force to the vehicle during the control, the driver's intention is not reflected. For this reason, this control apparatus is not preferable in view of safety when a fault of the control apparatus during the control is considered.
An object of the present invention is to provide a turn control apparatus for a vehicle, which reliably stabilizes the turn behavior of the vehicle when the vehicle is turned, while fully maintaining the safety of the vehicle.